Error(s) in re-building vignettes:
--- re-building ‘colorSpec-guide.Rmd’ using rmarkdown
dyld: lazy symbol binding failed: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

dyld: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

Error: processing vignette 'colorSpec-guide.Rmd' failed with diagnostics:
pandoc document conversion failed with error 6
--- failed re-building ‘colorSpec-guide.Rmd’

--- re-building ‘phenolred.Rmd’ using rmarkdown
This is colorSpec.  Version: 1.2-1.  Author: Glenn Davis [aut, cre].  Built: R 4.0.0; ; 2020-04-04 21:57:54 UTC; unix

Attaching package: 'spacesRGB'

The following objects are masked from 'package:colorSpec':

    RGBfromXYZ, metadata, metadata<-

dyld: lazy symbol binding failed: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

dyld: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

Error: processing vignette 'phenolred.Rmd' failed with diagnostics:
pandoc document conversion failed with error 6
--- failed re-building ‘phenolred.Rmd’

--- re-building ‘photoncounting.Rmd’ using rmarkdown
This is colorSpec.  Version: 1.2-1.  Author: Glenn Davis [aut, cre].  Built: R 4.0.0; ; 2020-04-04 21:57:54 UTC; unix
dyld: lazy symbol binding failed: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

dyld: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

Error: processing vignette 'photoncounting.Rmd' failed with diagnostics:
pandoc document conversion failed with error 6
--- failed re-building ‘photoncounting.Rmd’

--- re-building ‘blueflame.rnw’ using knitr
This is colorSpec.  Version: 1.2-1.  Author: Glenn Davis [aut, cre].  Built: R 4.0.0; ; 2020-04-04 21:57:54 UTC; unix

Attaching package: 'spacesRGB'

The following objects are masked from 'package:colorSpec':

    RGBfromXYZ, metadata, metadata<-

--- finished re-building ‘blueflame.rnw’

--- re-building ‘convexity.rnw’ using knitr
This is colorSpec.  Version: 1.2-1.  Author: Glenn Davis [aut, cre].  Built: R 4.0.0; ; 2020-04-04 21:57:54 UTC; unix
--- finished re-building ‘convexity.rnw’

--- re-building ‘emulation.rnw’ using knitr
This is colorSpec.  Version: 1.2-1.  Author: Glenn Davis [aut, cre].  Built: R 4.0.0; ; 2020-04-04 21:57:54 UTC; unix

Attaching package: 'spacesRGB'

The following objects are masked from 'package:colorSpec':

    RGBfromXYZ, metadata, metadata<-

18:01:06.469 WARN  colorSpec::product.colorSpec(). The returned matrix is ambiguous; because it depends on the splitting. Inspect the matrix carefully. 
18:01:06.492 WARN  colorSpec::product.colorSpec(). The returned matrix is ambiguous; because it depends on the splitting. Inspect the matrix carefully. 
--- finished re-building ‘emulation.rnw’

--- re-building ‘gallery.rnw’ using knitr
This is colorSpec.  Version: 1.2-1.  Author: Glenn Davis [aut, cre].  Built: R 4.0.0; ; 2020-04-04 21:57:54 UTC; unix

Attaching package: 'spacesRGB'

The following objects are masked from 'package:colorSpec':

    RGBfromXYZ, metadata, metadata<-

--- finished re-building ‘gallery.rnw’

--- re-building ‘inversion.rnw’ using knitr
This is colorSpec.  Version: 1.2-1.  Author: Glenn Davis [aut, cre].  Built: R 4.0.0; ; 2020-04-04 21:57:54 UTC; unix
--- finished re-building ‘inversion.rnw’

--- re-building ‘lens-aging.rnw’ using knitr
This is colorSpec.  Version: 1.2-1.  Author: Glenn Davis [aut, cre].  Built: R 4.0.0; ; 2020-04-04 21:57:54 UTC; unix

Attaching package: 'spacesRGB'

The following objects are masked from 'package:colorSpec':

    RGBfromXYZ, metadata, metadata<-

--- finished re-building ‘lens-aging.rnw’

--- re-building ‘optimals.rnw’ using knitr
This is colorSpec.  Version: 1.2-1.  Author: Glenn Davis [aut, cre].  Built: R 4.0.0; ; 2020-04-04 21:57:54 UTC; unix
--- finished re-building ‘optimals.rnw’

SUMMARY: processing the following files failed:
  ‘colorSpec-guide.Rmd’ ‘phenolred.Rmd’ ‘photoncounting.Rmd’

Error: Vignette re-building failed.
Execution halted